He had been due to join up with Chelsea in Holland on Wednesday night but the west Londoners decided the time was right to sell as they realised the inflammable mix of the manager and the 21-year-old would have flared up.

Mourinho said late on Wednesday: “The thinking was, first of all, the fact that Romelu was always very clear with us that in his mentality and his approach he was not highly motivated to come to a competitive situation at Chelsea.

“He wanted to play for Chelsea but clearly only as the first choice striker - and at a club of our dimension it’s very difficult to promise a player that status.

“That reduced, immediately, his desire to come to us. After that Everton came with an important offer and because we want to be inside the Financial Fair Play rules, you have to analyse these situations.”

Swift negotiations saw Lukaku agree a five-year contract worth £75,000 per week for Roberto Martinez’s men, after his outstanding 15-goal season on loan last term.

Everton agreed an initial £25m deal with add-ons that could be worth another £3m if Lukaku continues his free-scoring form and the Merseysiders make the top four or lift silverware.

And as he was introduced at the training ground on Wednesday, a delighted Lukaku said: “This is the best place for me to grow and develop as a footballer.

“Roberto has been very influential in the deal. He is someone who knows football and I want to learn from him and develop under him. He challenged me personally.

“I told him very quickly that I wanted to play under him. The rest was set up by the board and my agent. Now that I’m here I want to help my teammates.

“I decided very quickly that I wanted to come back here. I am 21, I need to play at a high level and with a good team. I needed to be in a place that felt right.

“I have the trust of the supporters here. I can grow and develop.

“I came back because I have a very good relationship with the players and the staff. I feel like I belong. I haven’t seen any of the lads but I have been in touch with all of them over the last two months.”

The Belgian was an instant hit for Martinez’s side after arriving on summer-window deadline day last year.

But while Chelsea had insisted he was being farmed out to further his education, he became embroiled in a series of verbal spats with his parent club, with Mourinho taking offence at a number of comments.

Martinez, however, praised Lukaku at every opportunity, nurturing the former Anderlecht man and making him the focal point of his side as Everton finished fifth to clinch Europa League football.

The bond he forged with the Spaniard persuaded him that Everton was the place to go and once Goodison chairman Bill Kenwright agreed to meet Chelsea’s reduced asking price, the deal was done swiftly.